A backup .zip exported on Windows failed to restore on every platform
(Web, Android, Windows): books restored with metadata but no files or
covers.
`appService.readDirectory` returns paths using the host separator, so on
Windows `file.path` is `hash\cover.png` (backslash). `addBackupEntriesToZip`
used that verbatim as the zip entry name, so entries were named with `\`.
Restore matches a book's files with `filename.startsWith(`${hash}/`)`
(forward slash), which never matched the backslash names, so every book
file was silently skipped.
Normalize the zip entry name to forward slashes when adding files. Entry
names are now cross-platform and restorable everywhere. Already-exported
broken backups need re-exporting from the fixed app.
Fixes#4703
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Huang Xin
febb0d9a69